Single sided or double sided flag: which back to buy

You hoist a club flag, walk to the pavement, and the crest faces the road the right way. From the kitchen the letters run backwards. That reverse is why a search for a single sided or double sided flag so often buys the wrong cloth. A mirrored back is the ordinary outdoor flag, because one layer stays light. Two panels with a block-out can show the words correctly from both directions, and that bag is heavier once the cloth is wet.

Products Compared read the amazon.co.uk listings in the Borussia Dortmund flag comparison on 19 October 2026, plus public notes from flags.co.uk, Flag Studio, Portfolio Display, Flagmakers and Borney. There is no lab test of opacity or wind load. A qualifying amazon.co.uk purchase can earn us a commission at no extra cost to you. Prices are the shelf figures captured then.

In short

If nobody has to read words from the reverse, buy the ordinary single layer and expect a mirror. If a name, a sponsor line or a crest must be right from the street and from the house, you need two correct faces, more weight, and a flag you take down sooner. Single sided and double-sided on a title do not, by themselves, tell you which cloth you will unpack.

Four phrases that get mixed up

Four labels get used as if they were one product. Only the bagged build keeps lettering readable from both directions.

• A blank reverse is printed on one face. Flag Studio warn that some makers use single sided for that empty back, so a pole whose reverse faces the road shows the street nothing.
• A print-through mirror is one polyester layer. The reverse is the same design, flipped left to right. flags.co.uk, who manufacture in Cambridgeshire, call this their mirror-image flag: lighter, and in their view more durable than a double construction. That is their advice, not a timed test.
• A sewn-through mirror is still one cloth. Flagmakers say a 115 gsm knitted polyester dyes through to about 95 percent of the face strength. Their 205 gsm Decotex does not show through, so they use it single-sided or as two panels.
• A bagged double layer is two panels, usually with a block-out, so both faces read correctly. Flag Studio say about twice the cost, and not for continuous outdoor flying. Portfolio Display say more than double in most cases. Those multiples are printer descriptions, not amazon.co.uk prices.

If the listing does not say blank, mirrored, or a second correct print, the word sided has not told you which cloth is in the packet.

A mirror back is the ordinary outdoor flag

UK outdoor makers recommend the mirror because one cloth stays lighter. flags.co.uk cite weight and how long they expect the cloth to last. Flag Studio fly print-through or stitch-through outside and say a moving flag is still recognisable in mirror. Portfolio Display say a mirror is most of what they make, on polyester they describe as 120 gsm. None of that is a wind-tunnel test.

A mirror is not a fault. The ink or the stitch did what a single layer does. Send the flag back only when you were sold a blank reverse, or two correct faces, and received something else. A broad stripe can still be named when the cloth moves. A sponsor line or a wordmark cannot. Buy the mirror when recognition is enough, and two correct faces when the letters are the purchase.

Cotton and linen do not print through

Flag Studio make small cotton flags as two panels because the fibre will not show ink on the reverse. That is a material limit, not a tougher outdoor flag. Dye-through polyester, such as the 115 gsm knit Flagmakers describe, gives you the mirror without a second panel.

A double sided flag when the words must be right

Choose the bag when someone must read words from both directions: a corner house, a road and a path, or a crest whose letters are the point. Two panels with a block-out are the true double-sided flag these UK makers mean. flags.co.uk also allow different designs on the two faces, which helps only if you want two artworks.

You pay for two prints, a liner and the sewing. Flag Studio say the bag pillows and strains fittings when wet, at about twice the cost, and they do not recommend it for continuous outdoor flying. Portfolio Display say more than double in most cases, want a rotating arm, and want it down in moderate wind. flags.co.uk call many double-sided flags the shorter-lived choice. That is advice, not a month-count for an ASIN in this hub.

Do not leave a bagged flag up because a line says weather resistant. The heavier cloth loads the header and the pole sooner than a single layer. Take it down when a light flag is already cracking in the wind.

Without a liner the front colour can shadow the back. With a liner each face stays clean and the flag holds more water. Borney put the same trade in one line: the mirror flies more easily, and the block-out costs more.

Weight, wind, and a short pole

A short fixed pole does not swing a wet double layer off the wind, so the bracket takes the load. These Borussia Dortmund listings include the flag and not a pole. Buyers of the official polyester flag expected a rod because a photo suggested one, and it was not in the box. Desert Cactus lists two metal grommets and no pole. Match a sleeve, a hook or two grommets.

No Beaufort number in these notes is a hard cutoff. Bring two panels and a liner in earlier than a 100 g single cloth. Portfolio Display's four to six months is an estimate for printed flags on an exposed site, not a lifespan for a Borussia Dortmund ASIN. This page did not fly either construction through a British winter.

Single sided or double sided on these listings

In the Borussia Dortmund flag comparison the top pick, ASIN B074W9G7JC, is the official polyester hoist flag: 150 cm by 100 cm, about 100 g, £10.97, 4.6 from 162 reviews. The listing says double-sided, indoor and room use, machine wash and a pole mount. It does not describe a second cloth or a liner. One hundred grams on 1.5 square metres is too light to treat that word as Flag Studio's bag. Reviews mention a garden and a facade. The heading still says indoor and room use.

Desert Cactus states a mirrored reverse on 3 ft by 5 ft cloth, about 152.4 cm by 91.4 cm, 150D polyester, 181 g, with a canvas header, quadruple-stitched ends, two metal grommets and hand wash only. Prices in the capture run from £35.80 for flag K to £37.86 for flag E. Review files on those letters are one, two or three texts, or empty. 150D is denier, not grams per square metre, and 181 g is not proof of two panels.

The official viscose flag is 150 cm by 400 cm, about 6 square metres, at £63.21 with 4.6 from 234 reviews. Size and fibre come before the mirror question. The £10.97 flag is the top pick on review depth and price. On the text available, it is not a certified two-panel outdoor flag.

Symmetrical flags and flags with letters

Flip the design before you pay for two panels. The Germany flag has full-width black, red and gold bands and no off-centre charge, so a print-through reverse still reads as that flag. Added words do not survive the flip. The stripes do.

The Spain flag has symmetrical bands and a coat of arms that is not. A mirror changes the emblem, while the colours can still be named as Spain from a distance. Correct arms on the reverse need a true double construction.

A club crest sits with the Spanish arms. Desert Cactus states the mirror, so Borussia Dortmund's letters read backwards on that print. The £10.97 listing says double-sided and does not show the reverse, so a backwards photograph is not automatically a defect. You need the reverse described as blank, mirrored or a second correct print.